qubit

noun

qu·​bit ˈkyü-bət 

plural qubits

: a unit of computing information that is represented by a state of an atom or elementary particle (such as the spin) and can store multiple values at once due to the principles of quantum mechanics

And the most basic truth of quantum mechanics dictates that you cannot measure a qubit without destroying the superposition. The register that said 1 and 0 will randomly collapse into 1 or 0.

—George Johnson

compare bit entry 3 sense 1

Examples of qubit in a Sentence

Recent Examples on the Web

Google’s most advanced quantum computer has 105 qubits, or the basic building block of a quantum computer, while experts say 1 million or more qubits will be needed for useful applications. —Yeo Boon Ping, CNBC, 26 Mar. 2025

Meanwhile Google has reduced quantum computing’s error rate during complex analysis by increasing the number of qubits. —Peter Cohan, Forbes, 23 Mar. 2025

Quantum computers can use carefully orchestrated arrays of qubits to simultaneously consider all possible values, exponentially increasing the speed and breadth of calculations. —Lee Billings, Scientific American, 12 Mar. 2025

They're fitted onto a silicon chip, alongside other qubits made from superconducting material. —New Atlas, 28 Feb. 2025

Word History

Etymology

qu- (in quantum entry 2) + bit entry 4, probably formed with punning allusion to cubit

Note: According to the American physicist Benjamin Schumacher, in the acknowledgements to a paper ("Quantum coding," Physical Review A, vol. 51, issue 4 [April, 1995], p. 2747), "The term 'qubit' was coined in jest during one of the author's many intriguing and valuable conversations with W. K. Wootters, and became the initial impetus for this work."

First Known Use

1994, in the meaning defined above

Rhymes for qubit

• cubit